Field of the Invention
This invention relates to the preparation of alkyl acrylates. More particularly it relates to a continuous, catalytic process for the preparation of alkyl acrylates (AA).
In the process of upgrading and refining crude petroleum, an objective of the refiner is to separate chemical-grade feedstocks from fuel-grade feedstocks. Chemical grade feedstocks generally afford a higher return because the products derived from them are substantially more valuable to the ultimate consumer of the products. One such family of petroleum derived products is the acrylate group. Acrylates are presently made from propylene in a two-step process. By this process propylene is oxidized in the vapor phase over a heterogeneous Co-Fe-Bi-Mo catalyst to acrolein. The acrolein is subsequently oxidized to acrylic acid over a second heterogeneous catalyst which typically contains Mo, Va and W. The yield of acrylic acid is 80 percent in two steps. The lower alkyl acrylates (AA) are produced by esterification while the higher acrylates are produced by transesterication of the lower acrylates. Most of the acrylic acid produced is converted to either methyl or ethyl acrylate for eventual use in surface coatings, fibers and plastics. The overall process starts with the propylene and produces methyl or ethyl acrylate in three steps.
Thus, it is an object of the present invention to prepare methyl or ethyl acrylate from ethylene, carbon monoxide, oxygen and the appropriate alcohol in a two-step process by the oxidative carbonylation of ethylene and CO and methanol.